Posted by alexandra_k on December 23, 2004, at 16:22:51
Concluding Remarks
The following table is a specification of the kind of anomalous experience that may be relevant to four of the eight delusions that feature in Davies et al’s battery. If this analysis of the content of the delusional experience is accepted and it is granted that the relevant anomalous experience is not a perceptual one and that the delusional subject does not have rational grounds to doubt the information provided by their experience then it would seem that we do not need to appeal to cognitive bias and / or deficit to account for the kinds of delusional utterances that are characteristic of these delusions.
Capgras
This person is unfamiliar to me
Frégoli
This person is familiar to me
Thought Insertion
That wasn’t my thought
Alien Control
That wasn’t my action
If the content of the Capgras subjects experience is that ‘this person is not familiar to me’ then subjects would be expected to respond by countering the claims that others make regarding the identity of the person with denials and statements that are characteristic of the Capgras delusion. If, on the other hand the content of the delusional experience is a general or vague experience of dissonance, or notification that some ‘unspecified element has changed’, as Maher explicates the content of the anomalous experience and as Davies et al., firstly take it to be, then delusion would not seem to be an inevitable result of that sort of experience. In this case there would not seem to be any intrinsic feature of the anomalous experience that would determine that the subject must develop a delusion in response to it.
Davies et al. use a very general construal of the anomalous experience to establish that a second factor must be required. They then refine the nature of the experience in order to maintain that the delusional error is in accepting that rich experience to be veridical when there is rational grounds to doubt. They do acknowledge that one could simply object to their counter-examples by maintaining that the experience of delusional subjects is different from the experience of non-delusional subjects. It would seem, however, that such examples provide a challenge to the line that anomalous experience is sufficient for delusion and the burden is placed on one-factor theorists to specify in more detail the nature of the anomalous experience that is supposed to be sufficient for delusion.
In this paper I have attempted to argue that it may well be plausible to pack a fairly rich content into the delusional subjects’ anomalous experience, and that that rich content may make it inevitable that delusion is the result of such experiences. If we consider the relevant anomalous experience to arise from a disconnection between perception and affective response then it would not seem that the delusional error is in accepting just any kind of erroneous perception to be veridical, as Davies et al. maintain. If delusional subjects are unable to reality test with a properly functioning mechanism then such a line on the nature of the anomalous experience is able to avoid the unwanted prediction that Davies et al., note, though it may also be seen to bring us back to Maher’s line on the sufficiency of certain kinds of anomalous experience for the production of delusion as it would seem that in accepting the information provided by the familiarity mechanism the delusional subjects reasoning processes are comparable to non-delusional subjects. In the case of delusions of misidentification (namely Capgras and Frégoli) the relevant anomalous experience would seem to be a disconnection or discrepancy between perception and affective response. In delusions of control (namely thought insertion and alien control) such an experience would seem to arise from a disconnection between intention and response (as Maher maintains and as argued in Chapter 2 of my Thesis). These disconnections produce an anomalous experience for the subject, and they are unable to use a properly functioning mechanism to ‘reality test’ as the only available mechanism is faulty / defective. Such a specification of the anomalous experience would rule out visual illusions as the sort of anomalous experience that is relevant to the production of delusion, though it may also be seen to bring us closer to Maher’s line on the sufficiency of certain kinds of anomalous experiences for the production of delusion.
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Bayne, T., & Pacherie, E. (2004). Bottom-up or Top-down: Campbell’s Rationalist Account of Monothematic Delusions. Philosophy, Psychiatry, & Psychology, 11(1), 1-11.
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Walkup, J. (1995). A Clinically Based Rule of Thumb for Classifying Delusions. Schizophrenia Bulletin, 21(2) 323-331.
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